請教一個問題

聲音的數字化是 44.1 KHz, 而圖像顯示是一秒24次。為什麼人耳探測聲音頻率需要多次信號，而人眼能夠瞬間感知光的頻率？

A question about sensory systems 

Music: a mathematical offering 

I am reading Music: a mathematical offering. Humans can hear frequencies from 20 to 20000 HZ. The maximum frequency that can be represented by digital signal is half the sampling rate. Compact disc is based on the sample rate of 44100 HZ, slightly more than double 20000 HZ, the highest frequency humans can hear. This is an example that technology standard is set according to human physiology. 

I got a question. The sampling rate of visual signals is 24 per second. Why human eyes can recognize light frequencies instantly while human ears need to hear consecutive signals to get sound frequencies? Or am I asking the right question?